The invention relates to a method for low loss control of a capacitive load C.sub.P, particularly a piezoelectric actuator.
With respect to electrical control, piezoelectric actuators behave in the same way as capacitors, which are charged either from a current source or a voltage source. Piezoelectric actuators are normally actuated via a so-called RC control. With this method, the piezoelectric actuator is charged from a voltage source, e.g. a large capacitor, by way of a switch and an ohmic resistance. The switch is opened for the discharging and a second switch is closed, subsequently short-circuiting the piezoelectric actuator via another ohmic resistance. The charging curve and thus also the elongation curve of the piezoelectric actuator can be selected freely owing to the choice of resistances. The great disadvantage of the RC control is the high power consumption of large actuators, meaning for a correspondingly high capacitance and high operating frequencies. In the process, the energy W=CU is converted in the resistances and the actuator into dissipation heat during each charging cycle and discharging cycle.